Electric control system



March 2, 1948. E. H. HAUG 2,436,803

ELECTRIC CONTROL SYSTEM Filed Aug. 23, 19 13 2300MSUPPLY l/OM Patented Mar. 2, 1948 ELECTRIC CONTROL SYSTEM Eugene H. Hang, Chicago, Ill., assignor to La Salle National Bank, Chicago, 111., as trustee Application August 23, 1943, Serial No. 499,597

1 Claim. 1

This invention relates to electric control systems and more particularly to a protective and sectionalizing control for electric lighting circuits and the like.

One of the objects of the invention is to provide an electric control system in which the several parts of the circuit may be sectionalized into independent closed circuits. According to one feature, one or more parts of the circuit may be isolated without effecting the remainder of the circuit.

Another object of the invention is to provide an electric control system in which the separation of the circuit parts is controlled in response to voltage. It will be understood that there may be one or several load circuits independently controlled each in response to the voltage thereacross.

Still another object of the invention is to provide an electric control system including a constant current regulator and a load circuit in which opening of the load circuit isolates it from the regulator and interrupts the supply of power to the regulator.

A still further object of the invention is to provide a voltage responsive control unit which operates in response to a predetermined voltage and which is not affected by oscillations in the circuit.

The above and other objects and advantages of the invention will be more readily apparent from the following description when read in connection with the accompanying drawing, in which Figure 1 is a diagram of a control system embodying the invention;

Figure 2 is a diagrammatic side view of one of the load switches; and

Figure 3 is a partially enlarged view of voltage gap.

The systems as shown in Figure 1, is adapted to connect a supply circuit Hi to one or more load circuits in series. As shown, there are two load circuits, one of which includes lines I! and I2 having a series of electric lamps 13 connected therein and the other of which includes lines l4 and 15 having a series of electric lamps l6 connected therein. It will be understood that the invention may be applied equally well where only one or where more than two load circuits are used.

The supply circuit H1 is connected to the input side of a constant current regulator I! which may be of any desired type such as that more particularly described and claimed in my copending application, Serial No. 469,974, filed December 24, 1942, now Patent No. 2,358,394. The regulator is the connected to the supply circuit l through switch contacts 18 controlled by a coil IS. A third contact 2i also controlled by the coil 19 is connected across the output circuit of the regulator. In operation of this switch mechanism, when the circuit is to be opened, the contact 21 is first closed before the contacts l8 are broken so that the contacts It! will always be broken with a v minimum of current flow therethrough.

The output side of the regulator is connected to a switch mechanism shown as comprising a double blade two position switch having a pair of center contacts 22 and 23 and four end con tacts 24, 25, 26 and 21'. The switch blades shown at 28 are inter-connected by a bar 29 as best seen in Figure 2 which carries a latch projection 3! adapted to be engaged by a slidable latch 32. The blades 28 are urged toward the contacts and 24 by a spring 33 and are held in engagement with the contacts 26 and 21 by the latch 32.

One side of the regulator output circuit is connected to the contact 22 and the other side thereof to the contact 21 as shown in Figure 1. The wire 7 ll of the first load circuit is connected to the center contact 23 and the other load wire is connected to the contact 25. Thus, when the switch is in its normal latched position as shown, the regulator output circuit is connected in series with the load circuit by the switch. When the latch is released, allowing the spring 33 to move the blades 28 into engagement with contacts 24 and 25, the output circuit of the regulator will be short-circuited and the load wires H and 12 will also be short-circuited through the switch to isolate the regulator circuit from the load circuit.

Operation of the latch is controlled by a coil 34 acting on the latch and connected in series with a resistor 35 and a gap 36 in response to the voltage across the load circuit. Under normal conditions the voltage is not suflicient to discharge across the gap 36 so that no current flows through the coil 34. Upon interruption of the load circuit resulting in an increase in the output regulator voltage or if the voltage should increase for any other reason, discharge across the gap will occur to energize the coil 34 and release the latch 32.

The first load circuit is adapted to be connected to the second load circuit by a switch similar to that just described and Whose parts are designated by the same reference numerals. In this switch, the center contact 22 is connected to the load wire II and the opposite center contact 23 is connected to the second load wire M. The

load wire I2 is connected to the contact 21 and the other second load wire I5 is connected to the contact 26. With the switch in its normal position as shown in Figure 1, load wires II and ill will be connected together and load wires l2 and l 4 will be similarly connected so that the two load circuits are in series. The gap 36 of the second load circuit is preferablyadjusted to discharge at a lower voltage: than the gap in the first load circuit so that upon an increase in voltage, the second load circuit will be cut out ahead of the first load circuit.

control circuit including supply wires 37. .s The wires 31 are connected through a, time clock mech anism 38 including a operati-n'g;.coil.i3'9-; an'dsa' switch 4| and through a switch blade 42 with the coil l9. Preferably, a manually operable switch 43 is connected in shunt around the clock switch M' so that the circuitmay be energized at will in-- dependently of the clock. The-clock may be adjusted as, for example, in a street lighting sys-' tem to turn-on the lights at a predetermined-hour in-theevening and to turn them off automatically at a predetermined morning hour.

The switch blade 42 is connected mechanically to' the blades 28' to move therewith sc'that when thelatch '32 of the firstswi-tch is released, the control circuit will be interrupted by opening of the'switch 42.- When this occurs, the'coil 19 will bede-energized-to open the switch contacts. B, first; however, closing the contact '2 I as explained above.

In order-to prevent accidental discharge across theixgaps .36 .and to insure that they will" discharge-ate. predetermined voltage value, the gaps are preferably constructed as shown in Figure3. As seenin this figure, the gap is formed by spaced partispherical members 44 mounted with their convex sides faoing-toleave a gap between them. I have found that in order to prevent corona discharge,.it is necessary that-the spherical members 4.4 have a radius at least as great as and preferably slightly exceeding the gap between them. With a gap formed in this manner, discharge will occur at the same 'voltage at all times and there will be nodischarge until the actual applied. voltage exceeds the value for which the gap is adjusted.

The surfaces of the spherical membersj lare preferably coated with an. active. material such, for example, as barium oxide or ceasium oxide. When coated inthis manner the'voltage drop across the gap after the voltage once reaches :a value high enough. to cause discharge, is substantially less. than with. an uncoated metal and the gap operates at a .lower temperature It'is also preferred to enclose the gap .as, .for example, in a glass envelope. as indicated at 45 which is .filled with an inert gas such as hydrogen. In this way, oxidation of the members 44 is prevented and the. life of the apparatus is materially increased.

The resistor 35' is included in thevoltage responsive unit .to dampen out oscillationsin the circuit which .mightfltend to build upsufilcient voltage to cause discharge across the gap. The inclusion of this resistor stabilizes the voltage responsive unit and insures that it will discharge only in response to'the actual voltage applied to the load circuit.

In operation, if one of the load circuits should be interrupted; for example, bybreakage of one'of the'lines: I 4 or. 15, the regulatorwill function to increase its output voltage in an attempt to maintain constant current flow through the circuit. As the voltage increases, it eventually reaches the point at which the second gap 36 discharges so that the latch 32 of the second switch is released allowing the switch blades 28 thereof to move into engagement with the contacts 24 and 25. This separates. the first and second circuits and, at the same time, short-circuits both circuits so that the second circuit may easily be tested and so that operation of the first circuit will not be interrupted. If a, break occurs in the first circuit-,Lthei voltage will continue to increase until the gap 36 of thefirst control switch discharges to al- ,-low. the switch to'move to its off position. This will short-circuit the output of the regulator and the input sidexof the first load circuit so that it can easily be tested and will, at the same time, open-the switch 42 so that the main switch contacts I3 will be open. g

The protective circuit including the coil 34, resistor 35 and gap 36 used for open circuit protection operates extremely fast and is capable of handling the current normally passing through the load circuit for the duration of the' fault. Themechanical switch is fast enough to open after the first cycle or two but the gap circuit is introduced to provide still faster protection in the order of one or two micro-seconds so that the peak voltage cannot exceed percent of its normal rated peak voltage. As soon as-th'e mechanical switch moves to its off-position; it lay-passes the gap circuit and relievesit-from carrying any current after the first one or two cycles.

While one" embodiment of the invention .has been shown and described in detail herein, it'is understood that this is illustrative only andis notintendedas a definition of'the scope of-the invention, reference being had forthis purpose to the appended claim.

What is claimed is:

An. electric control system for controlling connection of a source to a plurality of loadcircuits comprisinga constant current regulator .connected to the source, a protector switch with auxiliary contacts connecting theregulator .tothe first load circuit, said protector switch having a normal position in which itconnects the .regue lator'to the first load circuit and anioff position inwhich it short circuits the regular output-and the first" load circuit, means responsive to. the voltage across the first load circuit to control operation of the protector switch, a second. protector switch having a normal position inwhich it connects the first and second load circuits in series and an off position in which itshortcircuits the second load circuit, and means respone. sive to the voltage across the second load circuit to control operation of the second protector switch.

EUGENE H. HAUG.

REFERENCES CITED The .following references are of. record-inwthe file of this. patent:

UNITED STATES PATENTS" Number Name Date 1,930,088 Foulke- Oct. 10, 1933 2,354,786. Wall,v Aug. 1, 1 944 2,304,936 Young Dec. 15, 1942 2,226,041 Young, Dec,.24,, 1940 1,990,759 f Stone Eeb.'12 ,11,935 

